IPWAVE Working Group K. Sun
Internet-Draft Y. Kim
Intended status: Informational Soongsil University
Expires: September 10, 2020 March 09, 2020
Considerations for ID/Location Separation Protocols in IPv6-based
Vehicular Networks
draft-kjsun-ipwave-id-loc-separation-02
Abstract
ID/Location separation protocols are proposed for scalable routing,
enhancing mobility and privacy in IPv6-based vehicular networks. In
IPv6-based vehicular networks, ID/Location separation architecture is
expected to offer benefits. This document analyzes how ID/Location
separation protocols can adjust into IP based vehicular networks and
suggests requirements for efficient ID/Location separation in
vehicular networks.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases for ID/Location Separation Protocols . . . . . . . 3
3.1. Locator/ID Separation Protocol (LISP) . . . . . . . . . . 3
3.2. Identifier-Locator Network Protocol (ILNP) . . . . . . . 4
4. Gap Analysis . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 5
4.2. Mobility Management . . . . . . . . . . . . . . . . . . . 6
4.3. Security and Privacy . . . . . . . . . . . . . . . . . . 7
5. Acknkowledgement . . . . . . . . . . . . . . . . . . . . . . 7
6. Informative References . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
For vehicular networks, it is required to provide connection to the
Intelligent Transport Systems (ITS) for the driver's safety,
efficient driving and entertainment with fast mobility management.
Other scenarios besides V2I communication, like V2V and V2X
communication are also considered. Link layer protocols such as IEEE
802.11-OCB [IEEE-802.11-OCB] are already defined for low-latency and
alternative networks, and it is designed for enabling IPv6 as a
network layer protocol. Nevertheless, for using IPv6 in the
vehicular network, there are some requirements for optimization as
described in [ietf-ipwave-vehicular-networking]. These issues are
classified into IPv6 neighbor discovery, mobility management,
security and privacy.
In IETF, there are two major ID/Location separation protocols such as
LISP [RFC6830] and ILNP [RFC6740] for scalable routing, enhancing
privacy and mobility management. Currently ID/Location separation
concept is useful not only for decomposing ID/Location from an IP
address, but also for control/data plane separation which is a major
evolution of the Internet infrastructure. For the vehicular
networks, ID/Location separation protocols can be expected to meet
requirements and solve problem statements discussed in IPWAVE WG.
This document describes use cases for applying ID/Location separation
architecture to IPv6-based vehicular networks, and analyzes how such
protocols can meet requirements for IPv6 in vehicular networks.
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2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. This
document uses the terminology described in
[ietf-ipwave-vehicular-networking], [RFC6830], [RFC6740].
3. Use Cases for ID/Location Separation Protocols
3.1. Locator/ID Separation Protocol (LISP)
Traffic Control Center in Vehicular Cloud
*-----------------------------------------*
* *
* +----------------+ *
* | Mapping System | *
* +----------------+ *
* ^ *
* MS/MR | *
*--------------------v--------------------*
^ ^ ^
| | |
| | |
RLOC1 v v RLOC2 v RLOC3
+--------+ Ethernet +--------+ Tunneling +--------+
| RSU1 || RSU2 || RSU3 |
| (xTR) | | (xTR) | | (xTR) |
+--------+ +--------+ +--------+
^ ^ ^
+----:------------------:---------+ +--------:---------+
| : V2I V2I : | | V2I : |
| v v | | v |
+--------+ | +--------+ +--------+ | | +--------+ |
|Vehicle1|===> |Vehicle2|===> |Vehicle3|===>| | |Vehicle4|===>|
| (EID) || (EID) || (EID) | | | | (EID) | |
+--------+ V2V +--------+ V2V +--------+ | | +--------+ |
| | | |
+---------------------------------+ +------------------+
LISP Site-1 LISP Site-2
Wired Link Wireless Link ===> Moving Direction
Figure 1: LISP Use Case Scenario in IP-based Vehicular Network
Architecture
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Figure 1 describes a vehicular network architecture with the LISP
protocol. A single LISP site can have multiple RSUs with the
function of LISP Tunnel Router (xTR) to communicate with other LISP
sites. In the figure, we assume that Vehicles 1, 2 and 3 belong to
LISP site 1 and Vehicle 4 to LISP site 2. IPv6 addresses for
wireless interfaces of each vehicle are mapped to unique End-Point
IDs (EIDs), which can communicate with other EIDs in the same LISP
site same as a legacy IPv6 operation. That is, vehicles are able to
communicate with an RSU by V2I communication at the same time with
other vehicles in the same LISP site by V2V communication.
Traffic control center in the vehicular cloud is appropriate to
deploy a mapping system, since it is a point accessible from all
RSUs. When vehicles enter each LISP site and attach to an RSU, the
RSU sends a Map-Register message to the mapping system including
vehicle's EID and RLOC of the attached RSU. After registration, the
vehicle can be provided with reachability from other LISP sites or
non-LISP sites. In the figure, for the communication between vehicle
4 and vehicle 3, RSU 3 which is the attachment point of Vehicle 4
should request for the RLOC of vehicle 3 from the mapping system by
sending Map-Requests message. After receiving mapping information of
Vehicle 3's EID and its RLOC in Map-Reply message, RLOC 3 can forward
packets via the IP tunnel between xTR (e.g., RSU 2 in this figure)
assigned to vehicle 3. Note that several data plane protocols (e.g.,
SRv6, etc.) can be used with LISP control plane functions.
3.2. Identifier-Locator Network Protocol (ILNP)
In the ILNPv6, an IPv6 address is replaced with an Identifier-Locator
Vector (I-LV). The I-LV has a 128-bit length allowing it to be
applied to the current IPv6 header without modification. [RFC6740]
describes in detail how an I-LV value can replace an IPv6 address at
the same time how it can work in the current IPv6-based
infrastructure. In [RFC6741], the details of the ILNPv6 packet
header, locator subnetting and new DNS resource record type for
mapping I-LV values are defined.
A vehicular network architecture for supporting ILNP is shown in
Figure 2. Most of the components are similar with the architecture
described in [ietf-ipwave-vehicular-networking]. Every Vehicle can
have more than one NID to connect to a network, and the IPv6 address
for communication is represented as a combination of Node Identifier
(NID) and Locator. Site Border Router (SBR) can be implemented in an
RSU or border of ILNP subnet site, which should have a routing table
having the mapping information of I-LV values for forwarding packets.
A DNS server can be deployed in the vehicular cloud which is
accessible from both in ILNP site and external Internet.
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Traffic Control Center in Vehicular Cloud
*-----------------------------------------*
* *
* +-----------------+ *
* | DNS Server | *
* +-----------------+ *
* ^ *
* | *
*--------------------v--------------------*
^ ^ ^
| | |
+---------------------+ |
| SBR | |
+---------------------+ |
| | |
v v v
+--------+ Ethernet +--------+ +--------+
| RSU1 || RSU2 ||RSU3/SBR|
+--------+ +--------+ +--------+
^ ^ ^
+----:------------------:---------+ +--------:---------+
| : V2I V2I : | | V2I : |
| v v | | v |
+--------+ | +--------+ +--------+ | | +--------+ |
|Vehicle1|===> |Vehicle2|===> |Vehicle3|===>| | |Vehicle4|===>|
| (I-LV) || (I-LV) || (I-LV) | | | | (I-LV) | |
+--------+ V2V +--------+ V2V +--------+ | | +--------+ |
| | | |
+---------------------------------+ +------------------+
Subnet-1 Subnet-2
Wired Link Wireless Link ===> Moving Direction
Figure 2: ILNP Use Case Scenario in IP-based Vehicular Network
Architecture
4. Gap Analysis
4.1. Neighbor Discovery
In both cases of LISP and ILNP, the usage of the existing neighbor
discovery message defined in [RFC4861] is possible without
modification. In LISP, Vehicles and RSUs in the same LISP site can
exchange ND/NA messages for routing by EID configured as IPv6 format.
Also, ILNP can operate the neighbor discovery for the configuration
of an I-LV value as the I-LV for ILNPv6 occupies the same bits as the
IPv6 address in the IPv6 header[RFC6740]. Thus, for vehicular
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networking, it is expected that the same solutions already mentioned
in [ietf-ipwave-vehicular-networking] (e.g., new ND option
[ID-Vehicular-ND]) can also be applicable in the ID/Location
separation architecture.
4.2. Mobility Management
One of the advantages for using LISP is that mobility management can
be provided efficiently, when a device is roaming across different
LISP sites while maintaining its EID. The existing IP mobilty
management schemes such as MIP or PMIP require an anchor function
(e.g., Home Agent and Local Mobility Anchor) to maintain the IP
address of a mobile node when the mobile node moves. They can
construct a non-optimized forwarding path between the anchor and
current attachment point of the mobile node. In LISP, however, a
forwarding path can be optimized by updating EID-RLOC mapping
information and establishing an IP tunnel between the xTR of the
coresponding node and the xTR of the current mobile node's
attachement point. This provides advantages for easly optimizing a
forwarding path especially the vehicular networks where the
connection point of the mobile node can be move fast away from its
initial attachment point. In the vehicular networks, a vehicle with
an EID will roam much faster and it means that the mapped RLOC will
be changed more frequently. For faster RLOC assignment, a predictive
RLOC algorithm for roaming-EID is proposed in LISP WG
[draft-ietf-lisp-predictive-rlocs]. Using this algorithm, it
predicts the moving direction of a vehicle with a roaming-EID,
registers predictive RLOCs as a list to the mapping system, and
replicates packets to each RLOC in the list. It can minimize packet
loss while maintaining transport session continuity.
In ILNP, mobility management is classified into host mobility and
network (or site) mobility. For vehicular networks, host mobility
scenario is suitable [RFC6740]. When the vehicle moves to its
network attachment point and locator, it shortly becomes to belong to
a new site, it may send a Locator Update (LU) message to the
Corresponding Node (CN) and also send a request to the DNS server to
change its entry. Even though LU procedure is necessary, it causes
delay and packet loss during handover, and it may become a more
critical issue in the vehicular networks where the locator of a
vehicle is updated faster and more frequently. Therefore, ILNP needs
to minimize LU process including DNS updates for seamless mobility
management in vehicular networks. For example,
[ILNP-Sol-Wireless-Net] may be one possible solution that defines a
geological information server, which gives information of attachment
points nearby to devices to prepare handover, deliver its predictive
locator to the CN so that it can reduce packet loss and latency for
updating DNS.
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4.3. Security and Privacy
For supporting applications such as autonomous driving, the vehicular
networks require not only low latency and high bandwidth but also a
high level of security and privacy. The IPWAVE working group is
facing a mobility management challenge due to latency and management
complexity due to the exchange of signaling messages with mobility
anchor to establish a tunnel. In the ID/Location separation
approach, all vehicles maintain their unique ID while they are
allocated a locator in the fastest way without binding update
procedure. Nevertheless, a privacy problem still exists due to the
eacy access to the mapping system. Even though it is difficult to
track a device using a single RLOC or locator value since its locator
changes while moving across sites, on the other hand, since an EID or
identifier is defined as permanent, additional methodologies need to
be considered to secure device identifier information.
Another consideration is various communication links. In the
vehicular networks, not only V2I communication but also V2X
communication are required. It means that vehicles can directly
communicate with each other only with an ID value without a locator
which is allocated from the infrastructure. In this scenario, the
exposure of vehicle IDs to others (including hackers) occurs
frequently even though they do not access mapping system. In
[draft-iannone-pidloc-privacy], they describe about privacy issues
and requirements in ID/Location separation architecture.
Several existing works can provide enhanced privacy mechanisms in ID/
Location separation architectures. For example,
[draft-ietf-lisp-eid-anonymity] defines Ephemeral-EID which is
frequently changed by the device. For ILNP, identity privacy
supports using IPv6 privacy extensions for stateless address
autoconfiguration [RFC4941] and Locator Rewriting Relay (LRR)
component for locator privacy [RFC6748], can be solutions for
enhancing privacy in vehicular networks.
5. Acknkowledgement
We would like to thank Jahoon Paul Jeong as a contributor who
reviewed and gave comments for this version.
6. Informative References
[draft-iannone-pidloc-privacy]
Iannone, L., von Hugo, D., Sarikaya, B., and E. Nordmark,
"Privacy issues in Identifier/Locator Separation Systems",
draft-iannone-pidloc-privacy-00 (working on progress)
(work in progress), January 2020.
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[draft-ietf-lisp-eid-anonymity]
Farinacci, D., Pillay-Esnault, P., and W. Haddad, "LISP
EID Anonymity", draft-ietf-lisp-eid-anonymity-07(working
on progress) (work in progress), October 2019.
[draft-ietf-lisp-predictive-rlocs]
Farinacci, D. and P. Pillay-Esnault, "LISP Predictive
RLOCs", draft-ietf-lisp-predictive-rlocs-05(working on
progress) (work in progress), November 2019.
[ID-Vehicular-ND]
Jeong, J., Shen, Y., and Z. Xiang, "Vehicular Neighbor
Discovery for IP-Based Vehicular Network", draft-jeong-
ipwave-vehicular-neighbor-discovery-08(working on
progress) (work in progress), November 2019.
[IEEE-802.11-OCB]
"Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications", IEEE Std
802.11-2016, December 2016.
[ietf-ipwave-vehicular-networking]
Jeong, J., "IP Wireless Access in Vehicular Environments
(IPWAVE): Problem Statement and Use Cases", draft-ietf-
ipwave-vehicular-networking-13(working on progress) (work
in progress), January 2020.
[ILNP-Sol-Wireless-Net]
Isah, M. and CJ. Edwards, "An ILNP-based solution for
future heterogeneous wireless networks", PGNET
2013: Proceedings of the 14th Annual Postgraduate
Symposium on the Convergence of Telecommunications,
Networking and Broadcasting, June 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007.
[RFC6740] Atkinson, RJ., Bhatti, SN., and U. St Andrews,
"Identifier-Locator Network Protocol (ILNP) Architectural
Description", RFC 6740, November 2012.
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[RFC6741] Atkinson, RJ., Bhatti, SN., and U. St Andrews,
"Identifier-Locator Network Protocol (ILNP) Engineering
Considerations", RFC 6741, November 2012.
[RFC6748] Atkinson, RJ., Bhatti, SN., and U. St Andrews, "Optional
Advanced Deployment Scenarios for the Identifier-Locator
Network Protocol (ILNP)", RFC 6748, November 2012.
[RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
Locator/ID Separation Protocol (LISP)", RFC 6830, January
2013.
Authors' Addresses
Kyoungjae Sun
School of Electronic Engineering
Soongsil University
369, Sangdo-ro, Dongjak-gu
Seoul, Seoul 06978
Republic of Korea
Phone: +82 10 3643 5627
EMail: gomjae@dcn.ssu.ac.kr
Younghan Kim
School of Electronic Engineering
Soongsil University
369, Sangdo-ro, Dongjak-gu
Seoul, Seoul 06978
Republic of Korea
Phone: +82 10 2691 0904
EMail: younghak@ssu.ac.kr
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